We should first emphasize that you should always make a full backup on your own computer of everything related to your mail program before making any changes. Be sure to include messages and settings.

That said, with many email programs, including Outlook Express, Eudora, and Entourage, deleting a POP3 email account in the program usually should not delete the messages that have already been retrieved. You can usually delete or replace an email account in these programs without affecting or deleting previously downloaded messages.

However, some programs work a little differently. Read the information below before deleting accounts in those programs.

• Apple iPhone / iPad / iPod touch (iOS devices)
• Apple Mail
• Microsoft Outlook
• Mozilla Thunderbird

Apple iPhone / iPad / iPod touch (iOS devices)

When you delete a POP3 account from an iOS device, you will lose any mail that’s was stored in the local Sent and Trash folders on the device, as well as mail in the Inbox that has been deleted from the server. Be sure to read the small description of what will be deleted that appears on the screen when you choose “Delete Account”.

If you don’t want to lose this mail, you should disable the account instead of deleting it:

1. Go to Settings.
2. Tap Mail > Accounts (for iOS 14 or later), Passwords & Accounts (for iOS 13 or iOS 12), Accounts & Passwords (for iOS 11), Mail (for iOS 10) or Mail, Contacts, Calendars (for iOS 9 and previous versions)
3. Choose your POP3 mail account.
4. Change the “Account” setting to Off.
5. Tap Done to save the change.

If you’re using IMAP instead of POP3 on an iOS device, you would lose mail only if it’s being stored in the local Sent and Trash folders on the device instead of on the server. You can check if the Sent and Trash folders are being saved locally by following the steps on our iOS folder setup page and seeing whether it’s already set to save messages on the server.

Apple Mail

With the Apple Mail program, if a POP3 mailbox (an “account”) is deleted, it removes all messages associated with that mailbox, deleting them from your computer — which may have the only copy of a message if you’re not also storing them on our servers! It can also delete all local mail folders that normally show up under “On My Mac”.

You can "disable" an account, which keeps the messages stored on your computer — but it also hides them from your view, making them impossible to read or copy unless you re-enable the account.

Because of that, the only way to both save your mail and disable an old POP3 account is to first setup a new account (Apple Mail allows multiple accounts), then copy the old mail to the Inbox of your new account if it’s not already there (by simply dragging the messages).

We strongly recommend making a full backup of all email before copying messages and deleting accounts. Once you have verified that all mail has been copied to your new account, you can safely delete the old one.

If you’re asking this question because you’re switching from POP to IMAP, you should first create the new IMAP account in Apple Mail with the same address, then copy the mail to the IMAP account if necessary. Don’t delete the POP account until you’ve confirmed that all the mail you need has been copied to our servers and will therefore be visible from IMAP (you can use webmail to check what’s on our servers).

Microsoft Outlook

When you delete an account, you won’t lose any mail you’ve previously downloaded.

However, you may lose any mail filtering rules that you have created. You should export your rules so that they can be re-imported if necessary. To export the rules, go into the “rules wizard”, click Options, click Export Rules, and choose a name for the export file. You can import the exported rules later if necessary.

Mozilla Thunderbird

If you use Thunderbird and originally set up the account to use the “global mailbox” for a POP3 connection, or you use an IMAP connection, then it's okay to delete the account. However, if you set a POP account to save the messages into its own mailbox, then deleting the account will also delete the messages.